1. Field of the Invention
The present invention relates to a data transmission system for automated material handling system, and more particularly, to a data transmission system for automated material handling system in that, in the automated material handling system for transferring the products in course of manufacturing in the semiconductor manufacturing process or the liquid crystal display manufacturing process etc. to each manufacturing station, it switches the communication between the unmanned automatic transfer vehicle and the manufacturing station to the optical communication or the RF communication in readiness for the communication failure between the unmanned automatic transfer vehicle for master and the manufacturing station for slave, it transmits various input and output state data including the communication log data to the higher control system for master or the management computer system of slave/wireless data transmitter-receiver for slave by means of the master and/or slave device through the wire and wireless transmission and reception communication, thereby quickly coping with the operation error through the data analysis.
2. Description of the Related Art
In manufacturing processes of a liquid crystal display device and a semiconductor element, the manufacturing goods are transferred to the manufacturing stations of each manufacturing process by using an automated material handling system (AMHS), so that the corresponding goods are manufactured according to the manufacturing processes of each manufacturing station.
Generally, the automated material handling system includes an unmanned automatic transfer vehicle for transferring a carrier of receiving a semiconductor substrate or a liquid crystal substrate to the manufacturing station located on the manufacturing process line and transferring the carrier of again receiving the goods completely processed in the corresponding manufacturing station to the next manufacturing station.
As well known, depending on the movement method thereof, the unmanned automatic transfer vehicle includes an automated guided vehicle (AGV) for driving through the wheel, a rail guided vehicle (RGV) for driving along the guide rail located at the bottom, and an overhead hoist transport (OHT) for driving a guide rail installed in the ceiling. These transfer vehicles are moved to the corresponding manufacturing station by using the wheel itself or along the bottom rail or the overhead rail and it carries the goods onto or carries the goods out the manufacturing stations unit through the carrier.
The carrying/carrying out of the goods through the carrier is accomplished by the host computers mounted on the unmanned automatic transfer vehicle and the manufacturing stations under the control of the main controller for controlling the entire manufacturing lines.
At this time, in order to perform the carrying/carrying out of the goods between the unmanned automatic transfer vehicle and the manufacturing station, since the interlock operation thereof is accomplished in a state that the location on the carrying/carrying out between them is appropriately aligned, the unmanned automatic transfer vehicle and the manufacturing station are provided with an optical communication or wireless RF communication device so as to send and receives the necessary data.
As disclosed in a SEMI E84-0200A acknowledged as an international standard in 1999, in the interface construction of the automated material handling system using the optical communication device, the communication thereof is accomplished when the unmanned automatic transfer vehicle is arrived at the aligned location of the manufacturing station. Where the carrier is transferred from the unmanned automatic transfer vehicle to the manufacturing station, the communication contents such as an assigning signal (CS_O, CS_1) of the transfer port, a port use signal (VALID), a transfer request signal (TR_REQ), a working signal (BUSY), and a completion signal (COMPT) are transmitted from the unmanned automatic transfer vehicle to the manufacturing station. Also, the return request signal (L_REQ) and the return permission signal (READY) are transmitted from the manufacturing station to the unmanned automatic transfer vehicle. These signals are continually transmitted and received during the carrying and carrying out thereof.
However, during the carrying and carrying out of the goods between the unmanned automatic transfer vehicle and the manufacturing station, the operation sequence errors such as the communication disruption on account of the surrounding noise, the timing error between the unmanned automatic transfer vehicle for master and the manufacturing station for slave, and the reception error of the communication data from the adjacent master/slave device etc. can be occurred.
When these operation sequence errors are occurred, it is necessary to quickly grasp and handle the cause of the operation error so as to resume the operation thereof. Also, during the communication disruption, it is switched to other communication media so as to recover the communication thereof, thereby it is necessary to maintain the continuity of the operation.
However, in the conventional art, since it takes only the optical communication method using the IR communication, the communication distance thereof is short and the communication is an one-way communication. Also, during the communication error, there is a defect in that the operation of the manufacturing line itself is stopped until the error is solved.
Also, since the input and output signals are stored in a non-volatile memory such as an EEPROM, there is a problem in that the stored data should be deleted so as to store the data of a new cycle after the completion of the operation sequence of one cycle. Moreover, since the input and output logs are stored in the non-volatile memory such as the EEPROM, there is a problem in the implementation of high response speed owing to the time problem of deleting the pre-stored data so as to store the data of a new cycle. Furthermore, it is unsuitable for storing a lot of logs. That is, where the power is always supplied, it is not necessary to use the non-volatile memory so as to store large amounts of logs.
In addition, in case of the log data capable of identifying the error condition, since only the CPU itself timer value, that is, the relative time information between the signals existed in the master or the slave is stored, where a lot of log data is stored therein, the time information managed by the actual equipment is different from the pre-stored time information. Accordingly, there is a problem in that it is difficult to find the corresponding log during the error analysis.
In addition, since there is no communication means capable of directly transmitting the pre-stored data from the master of the unmanned transport vehicle or the slave of the manufacturing station to the separate control terminal or main controller, there are several drawbacks in that it is necessary to connect a separate data record means to the master or the slave so as to fetch the data.